In Chinese Patent Application CN 1051273A, entitled "plate shaped acid positive electrode", issued on May 8, 1991, an electrode plate is disclosed, which consists of two overlain electrically conducting plates with the same structure. The peripheries of the adjacent faces of two electrically conducting plates are provided with a main rib and each of electrically conducting plates is provided with substantially equal quantity of liquid incoming apertures. Meanwhile, the adjacent faces of two electrically conducting plates are coated with lead powder. In order to prolong the lifetime of electrode plate, the binding strength of the lead powder coating to the electrode plate is enhanced by providing crimping edge around peripheries of the adjacent faces, or arranging reinforce ribs on the adjacent faces of electrically conducting plates. This patent has raised the lifetime of the electrode plate at certain level. However, from the point of view of overall behavior of the accumulator, the over thickness of the electrode plate leads to the reduction of specific energy.
Another Chinese patent application CN 2073171U, entitled "lead acid accumulator having high specific energy and long lifetime", issued on Mar. 13, 1991, proposes a technical solution to reduce the thickness of an electrode plate in an accumulator, the way of which is to thin the plate grid of positive electrode plate to 4.0-7.5 mm. At the same time, the plate grid of a negative electrode plate is also to be thinned correspondingly, so that in a same container of the lead acid accumulator the number of electrode plates is increased relatively (i.e. the surface area is increased), and the polarization current for charging and discharging is reduced. Therefore, the specific energy is increased under the precondition that the lifetime is not damaged. However, the increase of specific energy by means of increasment of the surface area by thinning the electrode plate, generally speaking, will undoubtedly damage the lifetime and the strength of the electrode plates. Such disadvantage is just a problem difficult to be solved for several years in the accumulator field.
The technical solutions disclosed in the above mentioned two patents can not radically overcome the contradiction between the lifetime and the specific energy of an accumulator. Meanwhile, the recycling rate of cadmium is low, and the production cost is high.
Accordingly, the object of the present invention is to provide an electrode plate having high specific energy, high power, long lifetime, resistance to overdischarge and rapid charging, as well as its producing method.